29 April, 1999

4/29/99

At 5:30 AM, word came down from the bridge that there were icebergs and
loose ice in the vicinity. This could be potentially dangerous when the
ship is creeping forward with an expensive and heavy piece of equipment
hanging over the side. If a piece of loose ice were to strike the cable,
it could give the ZAPS sled quite a bump. Several of us climbed the 5
floors of stairs to the bridge to see the icebergs. We were greeted by yet
another of the many surreal sights destined for visitors to the ends of the
earth a pitch black sky with some kind of light precipitation casually
descending through our bright search lights which were trained and held on
a huge, double ice berg off to port. It was lit up in brilliant contrast
to the dark sky and dark sea by a spotlight whose path was defined by the
reflective trails of the precipitation, like shooting stars. The ‘bergs
were silently lurking, like barracudas or a nest of wasps, with little
“growlers” (they growl as they scrape against the side of the ship)
schooling around the ‘berg like buzzing wasps, occasionally slipping free
from the eddies that form around the berg’s environment. And the iceberg
does produce its own environment - Stephen Pyne describes in his book , The
Ice, how a ‘berg forms its own microcosm that is a self-similar picture of
the greater whole, Antarctica (students: what is self-similarity? What
popular branch of mathematics deals with this? What types of natural
systems demonstrate self-similarity?). Pyne shares how the iceberg
releases accumulated nutrients into the surrounding waters, which feed
algal blooms. These in turn attract zooplankton, which draw other
organisms, resulting in a “small marine biosphere.” Physically, not only
does the berg interact with currents, but it even lowers local air
temperatures, though the extent of this is extremely limited and a function
of its size.

Woke up again at 3 PM, went out to watch the sunset before the night’s work
began. Tonight it was fairly clear until a low hanging, furry, gray cloud
descended like a shaken blanket onto the surrounding seas, effectively
smothering out the sky from view. In the distance I saw another berg
stealthily creeping towards the ship. I knew that the mate on the bridge
would be watching the radar for its whereabouts in this limited visibility.

Back in the lab, the day-shift people are bringing in their equipment,
popping open film canisters onboard their towed instruments, and
downloading stored data from their CTD after a day of surveying an
interesting formation on Hook Ridge. Dr. Klinkhammer’s ZAPS data and
intuition (based on years of study and experience) point him to this
structure on the ridge that bathymetric data shows to resemble what Sven
Petersen said was a “caldera-like depression.” We shall begin a series of
ZAPS surveys of this area while the GEOMAR group interprets their data and
develops their film for further refinement of where the best possible
location to find a vent might be. So everyone is scurrying around, either
closing up shop from their shift, or preparing to start the next one. In
addition, tonight we are meeting as a group to discuss preliminary findings
and consequent plans for the remainder of the trip.

The interesting thing about this investigation is that it pulls so many
strands together the biology of classifying fauna in the search for key
indicator organisms, the geology of interpreting structure, the chemistry
of analyzing samples for elements and compounds, the engineering involved
in keeping the equipment in order and modify things on the fly. Yet all of
this is brought together under the umbrella of oceanography as all of the
data is interpreted and of all the consequent activity is coordinated.
Each brings his or her interpretation of the data to the meeting and
together a plan will be hammered out. As expected, when there are multiple
viewpoints, the discussion becomes more enthusiastic, with many more
interesting ideas and counter-ideas to weigh out and hold in mind in order
to arrive at a wholistic picture. Debate is natural, as keen minds each
process parts of the puzzle. After much discussion and impromptu
presentations, a plan is developed that has us at the ridge for at least
another night. We will explore the valley to determine the source of a
strong plume detected a few nights ago while we allow the sediment around
the caldera feature to settle from earlier activities conducted by the day
crew.

That’s all for tonight,

Shawn

Latitude (S): 62 11.3 Longitude (W): 57 16.4 Time (GMT):2021

Depth (m): 1023 Temp (C ): 2.6 Barometer (mbars): 1006.8

Wind Speed (m/s, knots): 6 11.7 Wind Direction (degrees) 278

Salinity (ppt) 34.1 Relative Humidity (%) 83.4

Student Weather Station

Barometer (mbars): 1014.4

Temperature (Celsius): 3.6

Relative Humidity (%):85.1

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